The invention relates generally to the field of rotating machinery. More particularly, the present techniques regard arrangements for securing a shaft or similar rotating member in a relatively long, hollow support member, such as a long bore outer hub assembly or mounting hub.
A wide range of rotating machinery is known and currently in use in a variety of industrial, commercial, and other applications. In many such applications shafts (or inner hubs) are supported for rotation within hollow members, such as outer or mounting hubs, and other mechanical supports. The shaft may be driven in rotation by a prime mover, such as an electric motor or engine, or may be linked to various power transmission elements such as chain drives, belt drives, transmissions, pulleys, and so forth. In all such applications mounting structures are typically required to support the rotating and non-rotating members with respect to one another in a manner sufficient to resist loading, while still allowing the rotating members to rotate freely.
When mounting rotating elements within a long bore, such as that found in certain outer or mounting hubs, several key considerations generally come into play. For example, the hub, any bearings supporting the hub in rotation, and any other associated coupling or mounting structures must be capable of withstanding the anticipated loads of the application. Moreover, the mounting structures should allow for the desired balancing or centering of loads within or about the bearing assemblies and hub configurations. In the case of a relatively long hub, such as in some gear reducer or pulley applications, it may be desirable to couple a single shaft (or some other rotating member) to each end of the hub to adequately support the shaft in rotation. Also, the mounting arrangement should prevent premature wear or fretting of the shaft and mounting components, thus maximizing the operating life of these devices. The arrangements should also permit use of hollow members having non-tapered (i.e., cylindrical) inner diameters or bores, if desired, to permit use, for example, of lower-cost and standard off-the-shelf outer and mounting hubs. Finally, the mounting structures would ideally be relatively straightforward in application, permitting the shaft (or inner hub) or outer hub configurations to be installed without undue expense, both in terms of time and parts. The latter concern extends to dismounting or disassembling the various components for faster servicing and replacement when necessary, resulting in less downtime and higher productivity.
Mounting structures have been developed that address these concerns adequately, although further improvement is necessary. For example, various tapered locking structures have been developed that force tapered members between a shaft and a mounting hub or bearing. A wide range of structures have been developed for forcing one or more tapered sleeves, for example, into engagement between a hollow member and a shaft. Such structures provide good mechanical support and allow for tight engagement of the hollow member and shaft. However, disassembly of such structures is often problematic, sometimes resulting in damage or destruction of mechanical components of the system, such as a shaft or tapered sleeve, for example. In certain known arrangements the mounting components are also relatively expensive to manufacture and can be difficult to assemble and disassemble.
There is a need, therefore, for an improved system for mounting a shaft or similar mechanical component within a hollow member. There is a particular need for a straightforward and reliable system for mounting rotating elements, such as shafts, within long bore hub configurations.